Long discontinuous reception (DRX) is a feature that will be implemented in a long term evolution (LTE) architecture. The implementation of long DRX preferably includes minimal signaling and is adapted to allow the user equipment (UE) a significant amount of time where it is not monitoring or measuring so that the UE can turn off its transmitter and receiver, thereby increasing battery life.
In LTE, turning off the transmitter is called discontinuous transmission or DTX and turning off the receiver is discontinuous reception or DRX.
In LTE, during DRX, a UE will periodically wake up for exchanges of messages or to make measurements. A DRX period or cycle is the time between UE awake times. The length of the DRX awake time is typically in the order of milliseconds.
With long DRX, the enhanced node B (eNB) knows when the UE will be awake and when it will not. The term “DRX desynchronization is meant to describe those times when the eNB does know exactly when the UE will be awake. There are situations when the UE is awake more than the eNB realizes and there are situations when the UE is awake less than the eNB realizes. These situations generally arise from miscommunications when the eNB signals to the UE to change the DRX. It may also arise when implicit DRX changes that are programmed in the eNB or UE are configured by the eNB in error. Such situations could, for example, include the application of a longer DRX value when no data activity has occurred for a certain period of time.